Evaluation of the Cost-effectiveness of Infection Control Strategies to Reduce Hospital-Onset Clostridioides difficile Infection

Key Points Question What is the most cost-effective infection control strategy for reducing hospital-onset Clostridioides difficile infection? Findings In this economic evaluation study, an agent-based simulation of C difficile transmission at a 200-bed model hospital found 5 dominant interventions that reduced costs and improved outcomes compared with baseline practices, as follows: daily cleaning (the most cost-effective, saving $358 268 and 36.8 quality-adjusted life-years annually), terminal cleaning, health care worker hand hygiene, patient hand hygiene, and reduced intrahospital patient transfers. The incremental cost-effectiveness of implementing multiple intervention strategies quickly decreased beyond a 2-pronged bundle. Meaning The findings of this study suggest that institutions should streamline infection control bundles, prioritizing a small number of highly cost-effective interventions.

Patients: Upon arrival to the hospital, patients are assigned a specific ward and room number. Each patient is also assigned an initial clinical state, which is subsequently updated every 6 hours based on probabilities in the model's discrete-time Markov chain. This discrete-time Markov chain was selected after extensive calibration from a subset of ten transition matrices run on the model simultaneously to account for population heterogeneity, as described by Barker, et al. 2 and Codella, et al. 4 The nine possible clinical states for patient agents include five in which the patient is not contagious: susceptible to colonization, non-susceptible to colonization, exposed to C. difficile, cleared (includes recent clearing of prior infection or colonization), and death, as well as four in which they are contagious: colonized (asymptomatic), infected (symptomatic), recolonized (sustained colonization, but asymptomatic), and recurrent infection (return of symptoms). Contagious patients can transmit C. difficile to nurses, doctors, visitors, and any environment they come into contact with, as well as other patients they meet in the ward common room. Conversely, they can become exposed from contaminated nurses, doctors, other patients, and the environment. Only one patient is assigned to each single-bed room at a time. Patients may change rooms within or between wards while at the hospital. These intra-and inter-ward transfers occur based on the patient transfer probabilities listed in Table 1.
Visitors: All visitors are assigned to a single patient and stay with them for an average visit duration of 15 minutes. [5][6][7][8] Visits occur in their patient's room or the ward common room. All visitors exit through the ward common room to leave the hospital. Visitors can become contaminated by the patient or environment they visit and can subsequently expose the environment in the patient's room or ward common room.
Nurses: Four nurses are assigned to each ward. 5,[9][10][11] They are based at their ward nursing workstation and leave it to care for patients in the patient rooms. Nurses only visit patients on their home ward. They spend an average of 4.7 minutes at each patient encounter. 5,[12][13][14] Patients are visited by nurses an average of five times every six hours. 5,12,15,16 Like visitors, nurses can become contaminated by the patient or environment they visit. Once contaminated, they can subsequently expose other patients or the environment in patient rooms or the nursing workstation.
Doctors: Two doctors are assigned to each ward. 5,17 They are based at their home ward physician workroom, but leave it to care for patients throughout the hospital. They spend an average of 10.8 minutes at each patient encounter. 5,[12][13][14] Each patient is visited by a doctor an average of one time every six hours. 5,12,15,16 Like visitors and nurses, doctors can become contaminated by the patient or environment they visit. Once contaminated, they can subsequently expose other patients or the environment in patient rooms or the physician workroom.
C. difficile transmission: Transmission occurs due to transient exposure to C. difficile spores from contagious patients and contaminated visitors, nurses, doctors, and the environment. The probability of contamination is proportional to the duration of exposure. Infection control interventions decrease C. difficile transmission by preventing (example: contact precautions) or clearing (example: hand hygiene, environmental cleaning) exposure and contamination. Table 1). Each single intervention was modeled at baseline, enhanced, and ideal implementation levels. 1. Healthcare worker hand hygiene improved nurse and physician hand hygiene compliance and increased the utilization of soap and water (versus alcohol-based hand rub) for known C. difficile patients. 2 Patient hand hygiene had similar effects on compliance and soap and water usage as the healthcare worker hand hygiene intervention, but for patient practices. 3. Visitor hand hygiene had similar effects on compliance and soap and water usage as the healthcare worker and patient hand hygiene interventions, but for visitor practices. 4. Healthcare worker contact precautions extended contact precautions for C. difficile patients until patient discharge, improved nurse and physician compliance, and increased the effectiveness of precautions at preventing contamination via an educational component aimed at improving donning and doffing techniques. 5. Visitor contact precautions had similar effects on contact precaution duration, compliance, and effectiveness as the healthcare worker contact precaution intervention, only for visitor practices. 6. Screening involved evaluating all asymptomatic patients for C. difficile colonization within 24 hours of admission via polymerase chain reaction testing of a stool sample or rectal swab. All C. difficile infection control policies except treatment were then implemented for any patients identified as colonized. 7. Daily cleaning increased the proportion of rooms cleaned daily by environmental cleaning staff and utilized sporicidal product in all patient, staff, and common rooms hospital-wide, regardless of C. difficile status. 8. Terminal cleaning increased the proportion of rooms cleaned by environmental cleaning staff at discharge, intra-ward, or inter-ward room transfer and utilized sporicidal product in all patient rooms hospital-wide, regardless of C. difficile status. 9. Reducing patient transfers decreased the rate of intra-and inter-ward transfers and prohibited room transfers for known C. difficile colonized or infected patients. This decreased the terminal cleaning burden for environmental cleaning staff and thus indirectly increased terminal cleaning rates.

Infection control interventions: Nine single interventions and eight multi-intervention bundles were modeled (selected parameters included in
Multiple intervention bundle strategies were developed in a stepwise approach, sequentially adding the most clinically effective enhanced single interventions until no additional effectiveness was obtained by enlarging the bundle. Hand hygiene (healthcare worker and patient hand hygiene), environmental cleaning (daily and terminal cleaning), and patient-centered (screening, patient hand hygiene, and patient transfer) bundles were also modeled, based on expert opinion that these interventions were likely to be implemented simultaneously in bundle form.